Radiological and clinical findings of isolated meningeal Rosai–Dorfman disease of the central nervous system

Rosai–Dorfman disease (RDD) with isolated central nervous system (CNS) involvement is an extremely rare disease. Most RDD of the CNS present as dural-based mass mimicking meningioma and other common lesions, which makes preoperative accurate diagnosis of great difficulty. We searched the pathology database in our hospital and 3 cases of RDD with isolated CNS involvement were finally included in our study. Radiological and clinical findings of these three cases were retrospectively analyzed. The lesions of 2 cases were dura-based against the cerebral convexity, presenting as a sheet-shaped thickened dura mater, another case was located just across the cerebral falx, the dural display in the center was intact. The 3 cases showed low signal intensity on T2-weighted image, obviously enhanced, significantly surrounding edema and finger-like protuberance but no invasion of the brain parenchyma or no sign of hyperplasia or sclerosis of the surrounding cranial bones. In conclusion, when we come across a disease that mimicking meningioma, especially when it manifests as the above radiological features, we should considered it might be a kind of proliferative disease of the meninges, such as RDD.